Issue with parenting tracked nulls to get Orientation for mesh
I found a solution to my problem.
The issue was that I added a Track to constraint to the mesh targetting the hand point therefore creating unpredictable spinning.
Therefore, after removing the constraint from the mesh, I just parent with the mesh to the bone with Automatic Weights, so the mesh will uniquely follow the bone and nothing else.
I keyframed the X Rotation of the bone to match the footage as best as possible.
Hope anyone will find this useful!